Conductor covering, method and compound for treatment thereof



Aug. 2, 1938. J. w. oLsoN CONDUCTOR COVERING, METHOD AND COMPOUND FORTREATMENT THEREOF Filed June 19, 1935 lNvENToR. c/BH/v WOL .so/v

lONUOQOU ATTORNEY.

iatented Aug. Z, 1938 UNiTD STATES ONDUCTOR COVERING, METHOD ANBCOMPOUND FOR TREATMENT THEREOF Joili W. Olson, Dobbs Ferry, N. Y.,assigner to Anaconda Wire e Cable Company, New York, N. Y., a.corporation ci Delaware Application June 19,

l 1i claims.

This invention relates to an improved conductor covering as well as themethod and compound for improving the conductor. The chief featurerelates to the inclusion of graphite in the jacket enclosing theconductor. The graphite can be applied by incorporating it in either thesaturant y cambric with a iibfrous jacket, such as a cotton braid, jute,or sisal braid and to saturate such. jacket by passing the jacketedconductor through al bath of compound usually of an asphaltic base. Thisbath has been either a ame retardant or non-flame retardant material.And it is old in the art to use saturants of wax, stearin pitch,petroleum base asphalts or natural base asphalts.

in wire or cable adapted to be pulled through ducts or' conduits, it hasheretofore been the practice to coat the saturated iibrous jacket withwax to increase the ease of pulling the same. When such wire has beenmade iiame retardant, stearin pitch has been applied over the saturatediibrous covering and then a thin coating of wax-like cornpound appliedover the stearin pitch. The waxes used have been low in` melting pointand frequently melted or iiowed if the cables were operated at themaximum temperature permitted by the insulated covering. Very highmelting point waxes which would meet the service conditions and whichwould still provide the lubricating coating on the saturated fibrouscovering are very costly and for this reason have not been applied toany large extent. Where a thin wax coating has been used over stearinpitch, in practice, the coating frequently rubs ofi when passed over aprojection or turn in the conduit or duct, this results in exposure ofthe adherent or tackystearin pitch and interferes materially with thepulling of the conductor into a duct. Conductor jackets treated withconventional impregnating compounds, when bent on a small radius, areopen to the objection that such bending has a tendency to cause disintegraticn of the compound with a consequent les'sening of its intendedprotective function.

The single gure in the accompanying drawing is an elevation with partsbroken away, illustrating an embodiment of the invention. The legends inthe drawing are to be interpreted in an illustrative rather than alimiting sense. g v

My invention aims to overcome these diiiiculties 1935, Serial No. 27,372

and to provide an improved product as Well as a method for treating thesame and a compound for saturating the jacket. in the" improvedconductor covering, the graphite incorporated will perl mit the same tobe readily pulled into conduits or 5 ducts Without sticking or dragging.The characteristics of the improved conductor covering are such as topermit o higher operating temperatures in service without injuriouseffect on the conductor covering. The improved covering can 10 beembodied in a flame retarding or non-flame retarding jacket dependingupon the constituents of the satur'ant or finishing material used.

The invention avoids the use of the old low melting point waxes andcontemplates the use of l5 graphite lled saturants or'lnishers toovercome the diihculty of sticking of coils or reels, or the diiculty ofpulling the covered wires or-cables into ducts or conduits.

The wax-like substances used heretofore have 20 been paramn and thelike, which have a relatively low melting point and are subject tomigration and sticking of the cable in the conduit or ducts.

In treating conductor coverings,according to my improved method, ifdesired, I may incorporate either Hake or `amorphous graphite in asaturant of bituminous or asphaltic material and pass the conductor withits enclosing fibrous jacket through this material. Or, I may iirst passthe jacketed conductor through a suitable satu- A rant'and then applythe graphite by passing the conductor through a container containinggraphite so that the same will adhere to the. saturated jacket,whereupon the asaturated and graphite 35 coated conductor can be passedthrough a die such asis commonly employed in the art.

The thus treated conductor covering may then be subjected to a nishingtreatment by passage through a bath consisting of` a compound ofbituminous material, asphaltic material and wax such as Montann wax,this bath also containing a substantial quantity of graphite.

Alternatively, thek jacketed conductor may be subjected to aconventional saturating treatment 45 in asphaltic or bituminousmaterials and tlrien subjected to a finishing treatment by passagethrough a bath carrying a substantial percentage of graphite. Regardlessof whether the graphite treatment of the jacket is accomplished duringthe saturating or nishing step, I deem it important toapply a suiiicientpercentage of graphite so that in the iinished product the coating willbe rendered non-sticky and endow the coated conductor withself-lubricating characteristics.

A suitable compound may be made up as follows:

Per cent Stearin pitch 35 Montan wax 15 Asphaltic material such asgilsonite 10 Graphite either amorphous or flake e 40 In some cases, I ndthat good results can secured by employing a smaller percentage ofgraphite, in which case I add carbon black and slate dust. Thus, analternative compound, approximately as iollows may be used:

. Per cent Btearin pitch approximately 30 Montan wax approximately 18Asphaltic material such as gilsonite 12 Flake graphite 15 Carbon black10 Slate dust 15 'me compound described is usually maintained with amixture of paraiiln and Montan wax and,V

then passing it through a heated die. But, it is to' be understood thatthe final paraffin and Montan wax treatment are not essential and thatthe graphite incorporated is suiiiclent to render the jacket non-stickyand self-lubricating.

Electric conductor jackets, when treated ac- .cording to the methodherein described and having incorporated therein the improvedbituminous, pitch or asphaltic vehicle carrying graphite, is endowedwith greatly improved characteristics and the improved character of theJacket is particularly noticeablev when the conductor is bent on a smallradius. Such bending does not tend to disintegrate or rupture theimpregnating materials and it is thought that the inclusion of graphite,due to its lubricating qualities, is a material factor in endowing thecomposition with this desirable characteristic.

While I have described specically the improved product. its method ofmanufacture and the composition oi saturating or nnlshing material usedin the treatment of the `iacket it is to be understood that thedisclosure is to be interpreted in an illustrative rather than alimiting sense since variations may be made without departure from theinvention as defined with particularity in the appended claims.

What I claimv is:

1. In the manufacture of .insulated wire, the method which comprisesenveloping a conductor with an absorbent jacket and subjecting saidjacket to treatment in a bath containing stearin pitch, Montan wax,asphaltic material and graphite.

2. In the manufacture of insulated Wire, the method which comprisesproviding a conductor having an absorbent jaclret and subjecting thejacket to treatment in a bath containing stearin pitch, Montan wax,giisonite, carbon black, slate dust Vand graphite.

3. Inthe manufacture of insulated wire, the method which comprisesproviding o. conductor having an absorbent jacket and subjecting thejacket to treatment in a bath containing stearin pitch, Montan wax,asphaltic material and graphite, the percentage of graphite in the bathbeing 'between iift'een and forty percent.4

'4. A conductor having an enveloping jacket ci .iibrous materialimpregnated with a compound comprising steal-in pitch, montan wats,asphaitic material and graphite, the latter being present in suificientquantity to endow 'the jacket with selilubricating characteristics.

5. A compound for treatment of conductor coverings comprising stearinpitch, Montan wax, as

phaltic material and graphite, the amount oi the latter ranging fromfifteen to forty percent of the total.`

6.' A compound comprising stearin pitch, Mon tan Wax, asphalticmaterial, flake graphite, carbon black and slate dust, the percentage oigraphite being not less than iifteen percent oi the total.

'1. A conductor having an insulating covering.

a Jacket oi' ibrous material enclosing the insulating covering, saidjacketbeing impregnated with a flame-resistant and moistureproofcomposition comprising stearin pitch and containing suiiicient graphiteto render the surface of the impregnated material self-lubricating.

B. The conductor of claim '1 in which the graphite comprises between l5and 40 per cent of said impregnating composition.

9. The conductor of claim 7 in which said impregnating composition alsocomprises Montan wax and asphaltic material.

10. A conductor having a covering of rubber insulation, a fabricenclosing said layer of rubber insulation, said fabric being impregnatedwith a flame and moistureprooflng composition comprising a stearinpitch, said composition having suiiicient graphite at its outer Vsurfaceto render it self-lubricating. f

11. An electric conductor having a covering ot rubber insulation, abraided covering of brous material enclosing said rubber insulation anda iiame and mistureprooiing composition impregnating said braidedcovering and comprising stearln pitch of between 15 to 40 per cent ofgraphite at its surface to render said surface self-lubricating.

' JOHN W. OLSON.

